Departmental Flags

The design of most departmental flag[s] is not specified by any of the Royal
Decree[s] concerning flags. In B.E.2440 [1897 AD], however, a decree was issued stipulating that the Royal Yacht's flag were to be used with the insignia of each specific department or unit, on the front in the top left hand corner. Royal permission had to be granted before anyone was allowed to use the flag.

In B.E.2460 [1917 AD], the year the "Trairanga" became the National flag following a special Royal Decree, all departmental flags adopted the design of the "Trairanga", but with the Insign[i]a of each department in the middle. This was carried out in accordance with a special Royal command which was published in the Royal Gazette.

Santiago Dotor, 12 November 1999

The governmental departments adopted different flags after the Second World War and I am not sure whether the national flag with emblem adopted for the departments in 1917 are now back in use.Jaume Ollé, 17 August 1997

Flag on State Buildings

image by Jaume Oll&eacute

Minister of Defense

5:6
image by Miles Li

2:3 White flag with Ministry emblem. Emblem consists of a dark blue
anchor set though a red chakra with light blue wings all crowned with a yellow Thai royal crown.
It's shown in Flaggenbuch with minor differences in artistic layout of the emblem, in ratio 5:6. Source: Album 2000Željko Heimer, 30 March 2003

The lion-like beast, Singha, is the true king of the forest. His roar echoes to great distances, terrifying all forest animals, great and small. He stands at the entrance of the Thai temple, guarding the sacred Buddhist teachings.

The Singha is therefore very suitable as a symbol of the Ministry of
the Interior, expected to guard the Thai state.
The anthroponym Singh is very common
in south-eastern Asia and the lion appears in the symbols of several various countries:

the lion is featured on the flag of Sri Lanka. In Sinhalese, "singha" means lion.

the seat of the government of Nepal is called Singha Durbar or "Lion's Palace."

The Customs Department, a part of the Ministry of Finance, has the duty of
collecting taxes and other fees from imports to Thailand. It also acts as a
police force to seize items that are illegal to import. Not much of the
department's history is known, nor any significance on the symbol used for the
department, which can be seen at
http://en.customs.go.th/data_files/1603091932431427107674.jpg.

The Prime Minister's Flag (B.E.2482) [1939 AD]
This is a white square, flag with a base measuring five-sixths of its length. In the middle stands the official state seal of the Prime Minister flanked by two creatures from Thai mythology – the "Kojasri" (a lion with an elephant's trunk) to the right, and the "Rajasri" (Lion) to the left, guarding a red chalice symbolizing democracy. Above hovers the Chakkri Crown in yellow.

This flag was first created following a special Royal Decree concerning flags, in B.E.2479 [1936 AD] – a turning point in the country's history, when Siam became a constitutional monarchy. The flag seen here was first used in B.E.2482 [1939 AD] and has been in use until B.E.2522 [1979 AD].

Santiago Dotor, 05 November 1999

5:7 White flag with red state seal topped with yellow Thai royal crown. Similar flag is shown also for Prime Minister, but
was apparently abandoned in 1979. Source: Album 2000

Flaggenbuch 1939 shows a white flag like the Regent's one with a 5:6 ratio, a centred escutcheon, no garuda and the two supporters described above – Kojasri and Rajasri – as Ministerpräsident. This relates better in some way to the above description, as the Singha Beer source image shows no "official state seal".Santiago Dotor, 20 January 2000

Minister (other than War Minister) 1939

5:6
image by Eugene Ipavec

Flaggenbuch 1939 also shows another similar flag to the Regent's, with a 5:6 ratio, the centred escutcheon alone and no supporters, as Staatsminister (außer Kriegsminister) or "Minister (other than War Minister)".
Santiago Dotor, 20 January 2000

Harbour Department 1911

The Harbour Departmental Flag (B.E.2454) [1911 AD]
This is a red flag with a white elephant in full caparison – standing on a raised dais facing the flagpole. In the top right-hand corner is a yellow crown above a black anchor with a yellow cord dangling from it.

The Governor's Flag
The Governor's Flag is a red flag with a white elephant – in full caparison – standing on a raised dais. In the top left-hand corner, there is a white circle, the diameter of which is one fourth of the width of the entire flag. In the middle of the circle stands the city's coat of arms. [Like the War Ensign 1891-1917 with city coat-of-arms inside a circle on the canton and a smaller elephant, slightly offset towards the fly.]

The flag, which first made an appearance in B.E.2434 [1891 AD], was known as "The White-Elephant-on-a-Platform Flag". The version shown here is the one used in B.E.2455 [1912 AD] by the Governor of Ayudhya during the reign, of King Rama VI. Governor's flag of this type were adopted for only a short period of time before their use was discontinued.